$fn = 64;

// --- Parameters ---
num_collars = 4;            // Number of hooks for collars
spacing = 55;               // Distance between hooks
hook_length = 35;           // Length of each hook
hook_dia = 12;              // Diameter of the hook shaft
end_cap_dia = 20;           // Diameter of the end cap to prevent slipping

base_height = 40;           // Height of the wall plate
base_thickness = 6;         // Thickness of the wall plate
padding = 35;               // Space on ends for mounting holes
corner_radius = 5;          // Radius for rounded corners of the base

screw_dia = 4.5;            // Diameter of mounting screws
screw_head_dia = 9.5;       // Diameter of screw head for countersink

// Calculated base width
base_width = (num_collars - 1) * spacing + (padding * 2);

// --- Main Assembly ---
difference() {
    // Main body
    union() {
        rounded_base();
        
        // Collar Hooks
        for (i = [0 : num_collars - 1]) {
            x_pos = (i - (num_collars - 1) / 2) * spacing;
            translate([x_pos, 0, 0])
                hook();
        }
    }

    // Mounting holes
    translate([-base_width/2 + 15, 0, 0])
        screw_hole();
    translate([base_width/2 - 15, 0, 0])
        screw_hole();
}

// --- Modules ---
module rounded_base() {
    hull() {
        translate([-base_width/2 + corner_radius, -base_height/2 + corner_radius, 0]) 
            cylinder(h=base_thickness, r=corner_radius);
        translate([base_width/2 - corner_radius, -base_height/2 + corner_radius, 0]) 
            cylinder(h=base_thickness, r=corner_radius);
        translate([-base_width/2 + corner_radius, base_height/2 - corner_radius, 0]) 
            cylinder(h=base_thickness, r=corner_radius);
        translate([base_width/2 - corner_radius, base_height/2 - corner_radius, 0]) 
            cylinder(h=base_thickness, r=corner_radius);
    }
}

module hook() {
    translate([0, 0, base_thickness - 0.01]) {
        // Fillet at the base for strength
        cylinder(h=4.01, d1=hook_dia + 10, d2=hook_dia);

        // Main shaft
        cylinder(h=hook_length, d=hook_dia);

        // End cap (45-degree chamfers for support-free 3D printing)
        translate([0, 0, hook_length]) {
            cylinder(h=4, d1=hook_dia, d2=end_cap_dia);
            translate([0, 0, 4])
                cylinder(h=4, d1=end_cap_dia, d2=hook_dia - 2);
        }
    }
}

module screw_hole() {
    // Screw shaft
    translate([0, 0, -1])
        cylinder(h=base_thickness + 2, d=screw_dia);

    // Countersink for screw head
    translate([0, 0, base_thickness - 3])
        cylinder(h=3.01, d1=screw_dia, d2=screw_head_dia);
}